Ubuntu: Add new domain / subdomain in apache

Navigate to /etc/apache2/sites-available. Create a file with your new domain name and add the following:

#file: mydomain.com
ServerName mydomain.com
DocumentRoot /root/directory/of/site

Source: http://linuxapachemysqlphp5.blogspot.com/2013/04/ubuntu-add-new-domain-subdomain-in.html

Restart Apache in all Linux distributions

Restart Apache

Ubuntu

service apache2 restart
/etc/init.d/apache2 restart
apache2ctl restart

CentOS

/etc/init.d/httpd restart
service httpd restart
/sbin/service httpd restart

Source: http://linuxapachemysqlphp5.blogspot.com/2013/04/restart-apache-in-all-linux.html